1. Field of the Invention
The present invention relates to an automatic seatbelt system for a vehicle designed to protect an occupant in an emergency situation of the vehicle and to enable a webbing to be automatically fastened to the occupant's body after he has been seated in a seat. More particularly, the present invention pertains to a driving force transmitting structure for use in such automatic seatbelt system.
2. Description of the Related Art
One type of automatic seatbelt system has already been proposed which employs a flexible thick-walled tape for transmitting tensile and compressive forces (see the specification of Japanese Utility Model No. 28552/1980).
In this conventional automatic seatbelt system, a thick-walled tape is provided with a plurality of openings at predetermined spacings, and a sprocket wheel of a driving means is engaged with the openings in the tape to transmit tensile or compressive force to the tape in the longitudinal direction thereof so as to activate an occupant restraining webbing to move along a guide rail through a slider, thereby allowing the webbing to be automatically fastened to or unfastened from the occupant's body.
The above-described conventional arrangement suffers, however, from the following disadvantage. Namely, the slider is connected to a portion of the tape in such a manner that the intermediate portion of the slider is passed through an opening provided in said portion of the tape, and therefore this opening needs to have a relatively large area. For this reason, the width and thickness of the tape must be sufficiently increased so that the sliding connecting portion, which has a relatively large opening area, can satisfactorily bear any tensile force applied thereto. Otherwise, it is necessary to employ a material for the tape which is able to bear a relatively large tensile force.